Lesson 6 - Growth and Yield Flashcards

1
Q

what is growth and yield, describe each one

A

body of information and techniques concerned with estimating future conditions for forest stands

growth: the change in some characteristic (attribute) of a tree or stand over time
yield: the quantity of some attribute of a tree or stand that is present at some point in time

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2
Q

explain MAI, CAI and PAI

A

mean annual increment: average growth of a tree or stand (yield at some age/age)

current annual increment: yearly growth, the difference in yield of two consecutive years

periodic annual increment: the average growth rate calculated over a specified time rate

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3
Q

how do CAI and MAI interact

A

yield curve is sigmoidal, characterized by three growth stages
youth characterized by a steady increase in both the CAI and MAI
maturity characterized by a slowing of the CAI coupled with an increasing MAI
senescence characterized by decreasing CAI and MAI

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4
Q

what is the culimination age

A

the age at which MAI is maximized

- stands managed with this as the rotation age, wood fibre is maximized

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5
Q

How do we use growth and yield information

A
  1. determining aac
  2. updating inventories
  3. choice of silviculture treatment
  4. returns on investments
  5. choosing rotation age
  6. long term planning
  7. comparison of production
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6
Q

What are the factors that affect the growth of trees

A

species, site quality, density, insects/diseases/damaging agents, managerial inputs

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7
Q

TSP vs PSP and what are they used for

A

temporary sample plot - measure the yield of stands, measured once
permanent sample plot - measure growth, revisited on many occasions

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8
Q

What are yield tables and what are the different types

A

display stand conditions at various ages in tabular format

normal yield tables: based on data from fully stocked stand
empirical yield tables: based on data from stands with average stocking
variable density yield tables: incorporate some measure of stand density
managed stand yield tables: predict growth in stands that have been silviculturally treated in some fashion

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9
Q

How can CAI be approximated

A

CAI = dbh x HT x W

W = width in metres of the last annual ring

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10
Q

how can MAI be approximated

A

MAI = (dhb2 x HT)/(4 x age)

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11
Q

What are some indicators of density

A

stems per ha, basal area per ha, average crown closure

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12
Q

how do you determine site quality

A

direct measures:

  • estimation from historical yield records
  • estimation based on stand volume data
  • estimation based on stand height data

indirect measures:

  • estimation from overstory species relationships
  • estimation from lesser vegetation characteristics
  • estimation from topographic, climatic, and edaphic factors
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13
Q

what is site index

A

an indicator of site quality, defined as the average height of a specified portion of the stand at some reference age

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14
Q

what assumptions underlie the use of site index

A
  1. the height of specific trees (usually dominants) is an indicator of site potential. the height of such trees is not influenced by non-site factors such as density and sire preparation
  2. site index is constant over time
  3. directions for calculating site index have been followed correctly in the field
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15
Q

When to use site index

A
  1. the species of interest must be present in the stand in sufficient numbers
  2. the stand must be within a specified age range
  3. the stand should be even-aged
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